<!DOCTYPE HTML>
<html>
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <title>style样式</title>
</head>
<body>
<h2 id="con">I love JavaScript</H2>
<p> JavaScript使网页显示动态效果并实现与用户交互功能。</p>
<script type="text/javascript">
  var mychar= document.getElementById("con");
  mychar.style.color = "red";
  mychar.style.backgroundColor = "#CCC";
  mychar.style.width = "300px";

</script>
</body>
</html>